The present invention relates to a shield for a combustion chamber of a gas-fired hot water heater whereby to provide heat concentration in the combustion chamber and on a lower heat transfer wall of the inner casing and also to reduce heat loss through the skirt and the bottom end of the water heater.
With known gas-fired hot water heaters using combustion chambers, there is a substantial heat loss through the lower skirt of the housing which is disposed adjacent the combustion chamber of the water heater and through the lower end portion of the housing. With the new designs of sealed combustions, combustion air is supplied through a vertical duct which is in registry with a supply hole provided in the skirt and therefore the insulation in that area is reduced. Also, the insulation between the lower skirt and the outer casing is not sufficiently thick and this results in heat loss as sealed combustion chambers become very hot. Accordingly, there is excessive heat loss through the skirt and the lower region of the hot water heater housing and the performance or efficiency of the hot water heater is reduced. There is therefore a need to overcome this problem.
It is a feature of the present invention to provide a shield for the combustion chamber of a hot water heater which substantially overcomes the above-mentioned disadvantage of prior art water heaters of this type.
Another feature of the present invention is to provide a shield for the combustion chamber of a hot water heater and which shield reduces heat loss through the skirt and outer casing and the bottom end of the hot water heater housing by about 30 to 50 percent over previous designs.
According to a further broad aspect of the present invention there is provided a shield for the combustion chamber of a hot water heater wherein the heat in the sealed combustion chamber is concentrated on the lower transfer wall of the inner casing while at the same time reducing heat loss through the skirt and the bottom end wall of the housing.
According to above features, from a broad aspect, the present invention provides a shield for a combustion chamber of a hot water heater. The heater has an inner casing for the containment of water to be heated by a combustion chamber disposed under the inner casing. A burner and a pilot are provided in the combustion chamber. A flue pipe extends from the combustion chamber to evacuate combustion gases. An outer casing is secured spaced about the internal casing and insulated therefrom by a thermal insulating material. A support base is provided at a bottom end of the water heater. A skirt is provided about the combustion chamber and spaced internally from a lower end portion of the outer casing. Air passage means is provided to supply air to the combustion chamber. A heat shield, formed of metal, is secured in the combustion chamber and encircles and is spaced about the burner and pilot. The shield is spaced from the skirt. Air aperture means is provided in the shield to permit passage of combustion air supplied through the air passage means. The shield provides heat concentration in the combustion chamber and on a lower heat transfer wall of the internal casing and also reduces heat loss through the skirt and a bottom end of the combustion chamber.